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got it.... still. no fabric is "waterproof" that i know of. not sil-nylon or cuben. for that matter it has to be that the weave of the fabric is tighter or it is treated in more coats / with better silicon.. guys that have used 100% silicon are getting good results right? so it must just be that scotchy is inferior. bummer cuz the price cant be beat. unless you go for that tyvek ugly tarp... not lookin so ugly these days lol

I'm not sure why you think "no" fabrics are waterproof. A high quality silnylon, good PU coated materials, cuban, etc., are for all intents and purposes, waterproof.

The DIY silnylon discussed in this thread uses a silicone sealant (caulk) disolved in mineral spirits to soak the fabric. After the mineral spirits evaporate and the silicone cures, the result is a fabric with the space between threads filled with silicone.

A silicone spray/scotchguard type product coats the surfaces of the threads but does not fill in the voids. It raises the surface tension (or something similar) of the fabric and causes water to bead up. Water "pounding" on the fabric (rain) can still be forced between the threads causing leaks. A bag made of this type material and pressurized will leak as well.

While my details may or may not be a little off, I believe the general ideas to be correct.

absolutely. i think we are all on the same page. the no fabric being waterproof wasnt my opinion. just a fact from wikipedia. but i understand what you mean when u say "for all intents and purposes" and i believe its that result we are all looking for. i appreciate the help. as ive never tried either. i simply use an 8x10 camo poly. tired of the roll at the bottom of my pack and the achy shoulders tho. i have seen silk and rayon umbrellas tho for many years. so there must be a way to treat these fabrics. if the proffessionals have found a way, then i can do it. at least thast always been my motto and it has served we well. really great info here its awesome to work these things out. we have a lot of talent and some serious IQ in the membership ranks. thanks all

Awesome thread! Although I wish I had read it before I made my DIY Silnylon 10x12 tarp. I would have had a much better process to get through and I would have know NOT to use the "Low Odor" spirits and use the regular spirits. It turned out great and it is VERY dry underneath. My wife was excited when it left her sewing room...

I've got a lot more reading to do as I'm only on post 337, in order to fix my problem from here http://www.hammockforums.net/forum/s...ad.php?t=61369 ...but this response threw me for a loop....are we not supposed to use the low odor minerial spirits? How did I miss that?

Ok, I think I'm back on track and low odor and/or odorless mineral spirits is fine to use. Correct?

1) Use heavy nitrate gloves, they will last longer in the mineral spirits.

2) Use of denatured alcohol is NOT recommended. We use this to smooth and clean up silicone but it does not mix with it.

3) Mineral spirits, paint thinner, or lacquer thinner, should all work, they are basically the same product just progressively stronger. Stay a way form white gas as it has a very low flash point. This translates to a high vapor rate and is quite dangerous.

4) I, personally, think the best way to do a project like this it to hang up your material tight, and then apply a thin runny coat, lots of excess and then use a Squeegee to "scrape" the excess off the fabric, you may need to Squeegee both sides so keep that in mind before hanging your fabric.

I think this would give you good penetration and remove all most all excess silicone form the material. This may also help with removing any air pockets left in the fabric itself. Possibility the cause of misting.

4) Do one layer. Silicone does not like to stick to it's self. Once silicone has fully cured adding additional silicone to it will only cause the second layer to flake off. I don't know what the mixing of silicone to mineral spirits does to the actual cure time to the silicone, it seems to vary with the product and mixing ratio from the different results people have with the product in a "jar". So you maybe able to touch up just made fabric, but I still think it would be better to do it in one shot.

And 5)

Given the availability of Sil-Nylon now days, Fall of 2012 VS Early 2008, why not just buy it?! Although it would be fun to do if you had the time, space and wherewithal.

I did not read the whole thread, but in the beginning someone came up with the idea of using vacuum for the soaking. That is used for treating fibers with epoxy, to remove bubbles and excess resin, and possibly for other reasons.

I just imagine that it would also help for impregnation of fabrics. Especially because it would likely remove air bubbles (and thus reach more percent of the fabric), and excess material, theoretically resulting in a more watertight and lighter end product.

Just been reading thru this thread a bit and was wondering if anyone has tried a 2 part silicone as aposed to the stuff out of a caulk tube. I used to use the stuf to make prosthetics and it was quite easy to work with. Not sure if it would make a difference just that because its 2 part curing not air curing you have more control overe it. Also the 2part stuff may impregnate the material better and therfore provide better water protection.

I haven't read all 44 pages so if iv missed something sorry for wasting your time.